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i've tested, now you can too

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This commit is contained in:
Brian West
2012-12-20 20:08:42 -06:00
parent d3fcfa8245
commit d67b96af8a
94 changed files with 25305 additions and 2005 deletions
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libs/libcodec2/src/phase.c
+63 -44
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@@ -22,20 +22,22 @@
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
along with this program; if not,see <http://www.gnu.org/licenses/>.
*/
#include "defines.h"
#include "phase.h"
#include "four1.h"
#include "kiss_fft.h"
#include "comp.h"
#include "glottal.c"
#include <assert.h>
#include <ctype.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
#define VTHRESH 4.0
#define GLOTTAL_FFT_SIZE 512
/*---------------------------------------------------------------------------*\
@@ -47,6 +49,7 @@
\*---------------------------------------------------------------------------*/
void aks_to_H(
kiss_fft_cfg fft_fwd_cfg,
MODEL *model, /* model parameters */
float aks[], /* LPC's */
float G, /* energy term */
@@ -54,7 +57,8 @@ void aks_to_H(
int order
)
{
COMP Pw[FFT_DEC]; /* power spectrum */
COMP pw[FFT_ENC]; /* power spectrum (input) */
COMP Pw[FFT_ENC]; /* power spectrum (output) */
int i,m; /* loop variables */
int am,bm; /* limits of current band */
float r; /* no. rads/bin */
@@ -63,19 +67,19 @@ void aks_to_H(
int b; /* centre bin of harmonic */
float phi_; /* phase of LPC spectra */
r = TWO_PI/(FFT_DEC);
r = TWO_PI/(FFT_ENC);
/* Determine DFT of A(exp(jw)) ------------------------------------------*/
for(i=0; i<FFT_DEC; i++) {
Pw[i].real = 0.0;
Pw[i].imag = 0.0;
for(i=0; i<FFT_ENC; i++) {
pw[i].real = 0.0;
pw[i].imag = 0.0;
}
for(i=0; i<=order; i++)
Pw[i].real = aks[i];
pw[i].real = aks[i];
four1(&Pw[-1].imag,FFT_DEC,-1);
kiss_fft(fft_fwd_cfg, (kiss_fft_cpx *)pw, (kiss_fft_cpx *)Pw);
/* Sample magnitude and phase at harmonics */
@@ -149,24 +153,26 @@ void aks_to_H(
This E[m] then gets passed through the LPC synthesis filter to
determine the final harmonic phase.
For a while there were prolems with low pitched males like hts1
sounding "clicky". The synthesied time domain waveform also looked
clicky. Many methods were tried to improve the sounds quality of
low pitched males. Finally adding a small amount of jitter to each
harmonic worked.
Comparing to speech synthesised using original phases:
The current result sounds very close to the original phases, with
only 1 voicing bit per frame. For example hts1a using original
amplitudes and this phase model produces speech hard to distinguish
from speech synthesise with the orginal phases. The sound quality
of this patrtiallyuantised codec (nb original amplitudes) is higher
than g729, even though all the phase information has been
discarded.
- Through headphones speech synthesised with this model is not as
good. Through a loudspeaker it is very close to original phases.
- If there are voicing errors, the speech can sound clicky or
staticy. If V speech is mistakenly declared UV, this model tends to
synthesise impulses or clicks, as there is usually very little shift or
dispersion through the LPC filter.
- When combined with LPC amplitude modelling there is an additional
drop in quality. I am not sure why, theory is interformant energy
is raised making any phase errors more obvious.
NOTES:
1/ This synthesis model is effectvely the same as simple LPC-10
vocoders, and yet sounds much better. Why?
1/ This synthesis model is effectively the same as a simple LPC-10
vocoders, and yet sounds much better. Why? Conventional wisdom
(AMBE, MELP) says mixed voicing is required for high quality
speech.
2/ I am pretty sure the Lincoln Lab sinusoidal coding guys (like xMBE
also from MIT) first described this zero phase model, I need to look
@@ -182,52 +188,64 @@ void aks_to_H(
a small delta-W to make phase tracks line up for voiced
harmonics.
4/ Why does this sound so great with 1 V/UV decision? Conventional
wisdom says mixed voicing is required for high qaulity speech.
\*---------------------------------------------------------------------------*/
void phase_synth_zero_order(
kiss_fft_cfg fft_fwd_cfg,
MODEL *model,
float aks[],
float *ex_phase /* excitation phase of fundamental */
float *ex_phase, /* excitation phase of fundamental */
int order
)
{
int m;
float new_phi;
COMP Ex[MAX_AMP]; /* excitation samples */
COMP A_[MAX_AMP]; /* synthesised harmonic samples */
COMP H[MAX_AMP]; /* LPC freq domain samples */
COMP Ex[MAX_AMP+1]; /* excitation samples */
COMP A_[MAX_AMP+1]; /* synthesised harmonic samples */
COMP H[MAX_AMP+1]; /* LPC freq domain samples */
float G;
float jitter;
float jitter = 0.0;
float r;
int b;
G = 1.0;
aks_to_H(model,aks,G,H,LPC_ORD);
aks_to_H(fft_fwd_cfg, model, aks, G, H, order);
/*
Update excitation fundamental phase track, this sets the position
of each pitch pulse during voiced speech. After much experiment
I found that using just this frame Wo improved quality for UV
I found that using just this frame's Wo improved quality for UV
sounds compared to interpolating two frames Wo like this:
ex_phase[0] += (*prev_Wo+mode->Wo)*N/2;
ex_phase[0] += (*prev_Wo+model->Wo)*N/2;
*/
ex_phase[0] += (model->Wo)*N;
ex_phase[0] -= TWO_PI*floor(ex_phase[0]/TWO_PI + 0.5);
r = TWO_PI/GLOTTAL_FFT_SIZE;
for(m=1; m<=model->L; m++) {
/* generate excitation */
if (model->voiced) {
/* This method of adding jitter really helped remove the clicky
sound in low pitched makes like hts1a. This moves the onset
of each harmonic over at +/- 0.25 of a sample.
//float rnd;
b = floor(m*model->Wo/r + 0.5);
if (b > ((GLOTTAL_FFT_SIZE/2)-1)) {
b = (GLOTTAL_FFT_SIZE/2)-1;
}
/* I think adding a little jitter helps improve low pitch
males like hts1a. This moves the onset of each harmonic
over +/- 0.25 of a sample.
*/
jitter = 0.25*(1.0 - 2.0*rand()/RAND_MAX);
Ex[m].real = cos(ex_phase[0]*m - jitter*model->Wo*m);
Ex[m].imag = sin(ex_phase[0]*m - jitter*model->Wo*m);
//jitter = 0.25*(1.0 - 2.0*rand()/RAND_MAX);
jitter = 0;
//rnd = (PI/8)*(1.0 - 2.0*rand()/RAND_MAX);
Ex[m].real = cos(ex_phase[0]*m/* - jitter*model->Wo*m + glottal[b]*/);
Ex[m].imag = sin(ex_phase[0]*m/* - jitter*model->Wo*m + glottal[b]*/);
}
else {
@@ -252,3 +270,4 @@ void phase_synth_zero_order(
}
}